The present invention relates to improvements in connecting terminals for printed circuit boards.
A connecting terminal of the general type to which the present invention relates is known from, for example, DE 4,239,480 Al and DE 196-11,762 Al. In this known connecting terminal, an actuating element is pivotally mounted in a housing. In one of the positions into which it is pivoted, this element presses the free elastic sidepiece of a clamping spring down into its open position, whereas, in a second pivoted position, the element releases the sidepiece of the spring, so that it can clamp a conductor which has been inserted. A curved cam surface on the actuating element causes the elastic sidepiece of the clamping spring to move the required distance between the open position and the clamping position. Since the actuating element is pivoted by means of a suitable tool such as a screwdriver, it is necessary to have such a tool available. In many situations where the connecting terminal is installed, however, this type of actuation can be inconvenient.
According to the invention, the actuating element is designed with two arms and can pivot around a journal. One arm of the actuating element is used to pivot the actuating element around the journal. A cam, which rises in the radial direction with respect to the journal is provided on the second arm of the actuating element. The cam engages with the clamping spring. The actuating element is pivoted into a position in which it is essentially parallel to the direction in which the conductor is introduced, that is, essentially parallel to the plane of the printed circuit board so that a conductor introduced into the connecting terminal can be clamped. In this first position, the cam releases the clamping spring, so that this can clamp the conductor. When the actuating element is pivoted into a second position, perpendicular to the first position, the cam of the second arm presses the clamping spring down and holds it in an open position, so that a conductor can be introduced into the clamping spring.
The actuating element can be pivoted easily and without the use of a tool. For this purpose, a lever is provided on the first arm of the actuating element, whereby the user can press a finger down on this lever to pivot the actuating element. The lever projects out essentially at a right angles from the arm of the actuating element. As a result, when the element is in the open position, the lever projects freely out from the front surface of the housing of the connecting terminal. As soon as the conductor to be connected is introduced into the housing and into the clamping spring, the user presses the lever down with a finger, whereby the actuating element is pivoted into the clamping position. In this position, the actuating element releases the spring so that the clamping spring can clamp the conductor. In this clamping position, the lever of the actuating element rests against the front surface of the housing, so said lever does not interfere with anything and does not project out beyond the outside contour of the housing.